Prosthetic foot

ABSTRACT

A prosthetic foot comprises a ground engaging bottom resilient member, a resilient heel member, and a resilient toe member that collectively circumscribe an open volumetric space. The members resilient compress to absorb compressive force throughout the entire stride of an individual utilizing the foot. The prosthetic foot stores energy during a heel strike phase of a gait cycle, and releases energy during a toe-off phase of the gait cycle in order to assist forward movement of a user. During the gait cycle, a loading response during the heel strike phase compresses the heel member and the toe member, and causes a deflection of the rear portion of the bottom member. Furthermore, an upward deflection of at least one of the bottom member and the toe member stores energy during the transition from the heel strike phase to the toe-off phase of the gait cycle.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/642,501, filed on Nov. 27, 2012, which is a 371 national phaseapplication of International Application No. PCT/US 11/33319, filed onApr. 20, 2011, which is a continuation-in-part of U.S. patentapplication Ser. No. 12/799,215, filed on Apr. 20, 2010, which is acontinuation-in-part of U.S. patent application Ser. No. 11/901,845,filed on Sep. 19, 2007, now U.S. Pat. No. 8,048,173; and thisapplication incorporates the disclosure of all such applications byreference.

FIELD OF THE INVENTION

This technology pertains to prosthetic devices. More particularly, thetechnology pertains to a prosthetic foot that, when utilized by anamputee, better replicates the action of a real foot and reduces therisk of injury to the amputee.

BACKGROUND OF THE INVENTION

Prosthetic feet are well known in the art. In use, such prosthetic feettypically do not replicate the action of a real foot and can generate“kickback” or “kickforward” reactions that increase the risk of injuryto an amputee utilizing the foot. Kickback is motion created by theprosthetic foot in a backward direction during the walking cycle.Kickforward is motion created by the prosthetic foot in a forwarddirection during the waling cycle. Either motion may create instabilityfor user if expanding or restricting the intended motion.

For an amputee, loosing bipedality may produce an involuntary anteriorlean or shift, forcing a constant imbalance or rebalance of posture. Theamputee no longer possesses voluntary muscle control on his involvedside due to the severance of the primary flexor and extensor muscles.The primary anterior muscle responsible for dorsiflexion (sagittal planemotion) is the anterior tibialis. Dorsiflexion is the voluntary anklemotion that elevates the foot upwards, or towards the midline of thebody. The primary posterior muscle responsible for plantarflexion is thegastro-soleus complex. It is a combination of two muscles working inconjunction: the gastrocnemius and the soleus. Plantarflexion is thevoluntary ankle motion that depresses the foot downwards, or away fromthe midline of the body. Therefore, it is desirable to have a prostheticfoot configured to promote increased muscle activity and promoteincreased stability for amputees, and it is desirable to provide animproved prosthetic foot which would better replicate the action of atrue foot. Furthermore, it is desirable to provide an improvedprosthetic foot which minimizes or eliminates “kickback” forces when thefoot is utilized to walk over a door jamb or other raised profile objecton a floor or on the ground.

SUMMARY OF THE INVENTION

An exemplary prosthetic foot is capable of mimicking the weight-bearingaction and momentum supplied by a foot. The exemplary prosthetic footapproximates the feel and range of motion of a user's normal stride. Inone embodiment, a prosthetic foot comprises a bottom member, a heelmember attached to a rear portion of the bottom member, and a toe memberattached to a front portion of the bottom member. The prosthetic foot isconfigured to store energy during a heel strike phase of a gait cycle,and release energy during a toe-off phase of the gait cycle in order toassist forward movement of a user. During the gait cycle, a loadingresponse during the heel strike phase compresses the heel member and thetoe member, and causes a deflection of the rear portion of the bottommember. Furthermore, an upward deflection of at least one of the bottommember and the toe member stores energy during the transition from theheel strike phase to the toe-off phase of the gait cycle.

In another embodiment, a prosthetic foot comprises a resilient bottommember having a first bottom end and a second bottom end, a resilienttoe member having a first toe end and a second toe end, and a resilientheel member having a first heel end and a second heel end. The first toeend is connected to the second bottom end of the resilient bottommember, and the resilient toe member is positioned over the resilientbottom member and directed towards the back of the prosthetic foot. Thefirst heel end of the heel member is connected to the first bottom endof the resilient bottom member, and the resilient heel member ispositioned over the resilient bottom member and directed towards thefront of the prosthetic foot. An open volumetric space is formed by theresilient bottom member, the resilient heel member, and the resilienttoe member. The resilient heel member and the resilient toe member mayoverlap to form the open volumetric space.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the presenttechnology will become better understood with reference to the followingdescription, appending claims, and accompanying drawings where:

FIG. 1 is a block diagram illustrating the component interaction of anexemplary prosthetic foot;

FIG. 2 is a perspective view illustrating a prosthetic foot constructedin accordance with an exemplary embodiment;

FIG. 3 is a side view further illustrating the prosthetic foot of FIG. 2prior to impact;

FIG. 4 is a side view illustrating the prosthetic foot of FIG. 2 at theimpact of the heel;

FIG. 5 is a side view illustrating the prosthetic foot of FIG. 2 afterit has moved, or rolled, from the heel strike of FIG. 4 to mid-stance;

FIG. 6 is a side view illustrating the prosthetic foot of FIG. 2 afterit has moved, or rolled, from the mid-stance of FIG. 5 onto the toe;

FIG. 7 is a bottom view illustrating the prosthetic foot of FIG. 2;

FIG. 8 is a side view illustrating alternate embodiments of theprosthetic foot of FIG. 2;

FIG. 9 is a back view further illustrating the prosthetic foot of FIG.8;

FIG. 10 is a graph generally illustrating the resistance-compressionprofile of a typical prior art prosthetic foot;

FIG. 11 is a graph generally illustrating the resistance-compressionprofile of an exemplary embodiment of a prosthetic foot;

FIG. 12 is a perspective view of an exemplary embodiment of a prostheticfoot;

FIG. 13A is a side view of an exemplary prosthetic foot with a convexbottom surface;

FIG. 13B is a side view of an exemplary prosthetic foot with anundulating bottom surface;

FIG. 14 is a perspective view of a prosthetic foot with an exemplaryconnector spring clamp; and

FIGS. 15A-15C illustrate various perspective views of an exemplaryprosthetic foot having a midline toe slot.

DETAILED DESCRIPTION

While exemplary embodiments are described herein in sufficient detail toenable those skilled in the art to practice the invention, it should beunderstood that other embodiments may be realized and that logicalstructural and mechanical changes may be made without departing from thespirit and scope of the invention. Thus, the following descriptions arenot intended as a limitation on the use or applicability of theinvention, but instead, are provided merely to enable a full andcomplete description of exemplary embodiments.

Briefly, in accordance with an exemplary embodiment, a prosthetic foothas improvements over a prior art prosthetic foot in that a more naturalmotion and response of the foot occurs during movement. In particular,the movement of the exemplary prosthetic foot replicates the naturalflex of a foot and supplies continuous energy to a person when stridingfrom heel to toe. With respect to general structure in an exemplaryembodiment, a prosthetic foot comprises a ground engaging bottomresilient member having a front end and a back end and an intermediatesection spanning between and connecting the front end and the back end;a heel resilient member having a rear end connected to the back end ofthe bottom resilient member, extending upwardly from the back end, and,having a forward end spaced apart from the rear end and the bottomresilient member; and, a toe resilient member having a proximate endconnected to the front end of the bottom member, extending upwardly fromthe front end and over the forward end of the heel resilient member, andhaving a distal end spaced apart from the proximate end, from the frontend, and above the heel resilient member. The bottom member, heelmember, and toe member are shaped and dimensioned and have a resistanceresponse to a compressive applied force such that when the compressiveapplied force compresses said prosthetic foot against the ground theintermediate section of the bottom member upwardly deflects from theground, and the toe member downwardly deflects toward the ground andcontacts the heel resilient member and deflects the heel member towardthe ground and toward the bottom member.

In another embodiment, a prosthetic foot comprises a ground engagingbottom resilient member having a front end and a back end and anintermediate section spanning between and connecting the front end andthe back end; a toe resilient member having a rear end connected to thefront end of the bottom resilient member, extending upwardly from thefront end, and, having a forward end spaced apart from the rear end andthe bottom resilient member; and, a heel resilient member having aproximate end connected to the back end of the bottom member, extendingupwardly from the back end and over the forward end of the toe resilientmember, and having a distal end spaced apart from the proximate end,from the back end, and above the toe resilient member. The bottommember, heel member, and toe member are shaped and dimensioned and havea resistance response to a compressive applied force such that when thecompressive applied force compresses the prosthetic foot against theground the intermediate section of the bottom member upwardly deflectsfrom the ground, and, the heel member downwardly deflects toward theground and contacts the toe resilient member and deflects the toe membertoward the ground and toward the bottom member.

In accordance with an exemplary embodiment, and with reference to FIG.1, a prosthetic foot 10 comprises a bottom member 11, a heel member 20,and a toe member 14. The three members 10, 14, 20 are structurallyconnected to form prosthetic foot 10 and configured to provide a naturalstride for a user. In the exemplary embodiment, prosthetic foot 10stores energy during the gait cycle and transfers the energy in order to“put a spring in your step.” The gait cycle, and specifically the stancephase, includes a heel strike phase, the mid-stance phase, and thetoe-off phase. The heel strike phase begins when the heel of the foottouches the ground, and includes the loading response on the foot. Themid-stance phase is when the foot is flat on the ground and the body'scenter of gravity is over the foot. The toe-off phase is the finish ofthe stance phase and ends when the tip of the foot is the only portionin contact with the ground, and the load is entirely on the toe.

Moreover, the three members 11, 14, 20 transfer energy betweenthemselves in a natural, true foot manner, as indicated by the arrows inFIG. 1. The loading response during the heel strike phase compressesheel member 20 and toe member 14, which in turn passes energy into, andcauses a deflection of, a rear portion of bottom member 11. Energy istransferred towards the front of prosthetic foot 10 during themid-stance phase. Furthermore, an upward deflection of at least one ofbottom member 11 and toe member 14 stores energy during the transitionfrom the mid-stance phase to the toe-off phase of the gait cycle. In anexemplary embodiment, about 90% or more of the heel strike loadingenergy is stored and transferred to toe member 12 for assisting thetoe-off phase. In another exemplary embodiment, about 95% or more of theheel strike loading energy is stored and transferred to toe member 12for assisting the toe-off phase. In yet another exemplary embodiment,about 98% or more of the heel strike loading energy is stored andtransferred to toe member 12 for assisting the toe-off phase. Prostheticfoot 10 may be designed to release the stored energy during the toe-offphase and assist in propelling the user in a forward direction.

Turning now to the additional drawings, which depict the exemplaryembodiments for the purpose of illustrating the practice thereof and notby way of limitation of the scope of the invention, and in which likereference characters refer to corresponding elements throughout theseveral views, FIGS. 2 to 7 illustrate one exemplary embodiment of aprosthetic foot

In accordance with an exemplary embodiment, and with reference to FIG.2, a prosthetic foot 10 comprises a first resilient flexion bottommember 11, a second resilient flexion heel member 20, and a thirdresilient flexion toe member 14. The three resilient members 11, 14, 20are structurally connected to form prosthetic foot 10 and configured toprovide a natural stride for a user. In one particular embodiment andwith continued reference to FIG. 2, first resilient flexion bottommember 11 includes a first bottom end 12 and a second bottom end 13,second resilient flexion heel member 20 includes a first heel end 21 anda second heel end 22, and third resilient flexion toe member 14 includesa first toe end 15 and a second toe end 16. First heel end 21 of secondresilient flexion heel member 20 may be connected to first bottom end 12of first resilient flexion bottom member 11. Furthermore, first toe end15 of third resilient flexion toe member 14 may be connected to secondbottom end 13 of first resilient flexion bottom member 11. In anexemplary embodiment, second heel end 22 can, if desired, be fixedlysecured to resilient flexion toe member 14. In an exemplary embodiment,resilient flexion members 11, 14, 20 may be fabricated together as aunitary member. In another embodiment, the end pairs 21-12 and 13-15 ofresilient flexion members 11, 14, 20 may be connected with adhesive,bolts, or any other desired fastener or fastening means. For example, anelastomeric washer layer may be placed between first toe end 15 andsecond bottom end 13, and adhesive layers on either side of the washermay be used to hold the components together. The elastomeric layer maybe neoprene, vulcanized rubber, polyurethane, or the like. Additionally,a layer placed between first toe end 15 and second bottom end 13 tofacilitate attachment of the members may be various shapes and variousmaterials as would be known to one skilled in the art. When prostheticfoot 10 is compressed against the ground, resilient flexion members 11,14, 20 flex and have a resistance response in which flexed members 11,14, 20 generate forces resisting such compression.

Furthermore, in an exemplary embodiment, prosthetic foot 10 may beconfigured to attach to a prosthetic leg. For example, second toe end 16may be shaped and dimensioned and adapted to be connected to anotherportion of a leg prosthesis. By way of example, and not limitation, inFIG. 2 a trapezoidal slot 17 is formed in second toe end 16 to slidablyreceive a trapezoidal finger 18 of an L-shaped member 19 that forms apart of a leg prosthesis. In another example, and as illustrated in FIG.8, an alternate way comprises shaping an end 16A of a flexible member 14to facilitate attachment of a prosthetic foot 10A to the lower end of aprosthetic leg, or to a prosthetic device attached to the remainingportion of an individual's leg.

In an exemplary embodiment and with reference to FIG. 3, resilientflexion bottom member 11 includes a bottom surface 24 and an uppersurface 25. Resilient flexion heel member 20 includes upper contactsurface 34. Resilient flexion toe member 14 includes lower contactsurface 33, and includes a ridge 32. When prosthetic foot 10 iscompressed and resilient flexion toe member 14 is compressed anddisplaced downwardly toward resilient flexion bottom member 11, ridge 32can contact upper surface 25 and permit the portion of resilient flexiontoe member 14 behind ridge 32 to continue to be downwardly depressedagainst resilient flexion heel member 20 and towards resilient flexionbottom member 11.

The compression of the prosthetic foot during motion results in theprosthetic foot changing shape. With respect to changing shape,resilient flexion members 11, 14, 20 extend around and partially enclosean open volumetric space 23. When prosthetic foot 10 is compressed toforce resilient flexion members 14 and 20 toward resilient flexionbottom member 11, the volume, or size, of space 23 decreases. As isunderstood, once the compression forces are withdrawn from prostheticfoot 10, resilient flexion members 14 and 20 expand away from resilientflexion bottom member 11, and the volume, or size, of space 23increases.

As would be appreciated by those of skill in the art, prosthetic foot 10can, for aesthetic reasons, be inserted in a hollow, pliable, resilientreplica of a foot that is made from rubber, another polymer, or anothermaterial. The use of such a housing or some other desired covering forprosthetic foot 10 ordinarily will not alter the functioning ofprosthetic foot 10 as described herein.

For increased understanding of the exemplary embodiments, in FIGS. 3 to6, it is assumed that prosthetic foot 10 is mounted on the lower end ofa prosthetic device, that the prosthetic device and prosthetic foot 10are mounted on an amputee or other individual and form at least aportion of an individual's leg, and that the individual is walking andis therefore utilizing the prosthetic device and prosthetic foot 10mounted on the lower end thereof. A ground, floor, or other surface 30illustrated in FIGS. 3 to 6 is variously shown as sloped upwardly,sloped downwardly, or level; this to indicate that the foot 10 generallyfunctions in a similar manner on sloped or flat surfaces.

FIG. 3 illustrates prosthetic foot 10 just prior to heel strike. At heelstrike on ground 30, prosthetic foot 10 is generally in front of theindividual's upper body, as is normally the case when a person iswalking. As previously discussed, energy storage occurs in prostheticfoot 10 as part of the loading response.

FIG. 4 illustrates prosthetic foot 10 shortly after heel strike. Afterthe bottom surface 24 on first bottom end 12 of resilient flexion bottommember 11 contacts ground 30, the user's weight, indicated by arrow W inFIGS. 3 to 6, compresses second toe end 16 downwardly in the directionof arrow A in FIGS. 3 and 4 such that lower contact surface 33 slidablycontacts upper contact surface 34 and resilient flexion toe member 14forces second heel end 22 of resilient flexion heel member 20 downwardlyin the direction indicated by arrows B in FIGS. 3 and 4. Upper contactsurface 34 slides over lower contact surface 33 in the directionindicated by arrow D in FIG. 4. As the user continues his stride afterheel strike, prosthetic foot 10 rolls from the heel strike position ofFIG. 4 to the mid-stance position illustrated in FIG. 5. In themid-stance position, the individual's leg and upper body are generallydirectly above prosthetic foot 10 and a larger proportion of theindividual's weight bears down on prosthetic foot 10.

When prosthetic foot 10 rolls over bottom surface 24 from the heelstrike position of FIG. 4 to the mid stance position of FIG. 5, thedownward displacement and compression of resilient members 14 and 20continues; however, at the same time resilient flexion bottom member 11is compressed, resilient flexion bottom member 11 flexes upwardly in thedirection of arrow C in FIGS. 3 and 5, and the convex curvature ofresilient flexion bottom member 11 flattens. The flattening of resilientflexion bottom member 11 may initiate at, or shortly after heel strike,but the flattening is preferably clearly pronounced at mid-stance. Asthe individual continues his stride after prosthetic foot 10 reachesmid-stance, prosthetic foot 10 rolls from the mid-stance position ofFIG. 5 to the toe strike position of FIG. 6.

When the toe strike position is reached, as illustrated in FIG. 6,resilient flexion bottom member 11 normally has preferably resilientlyreturned at least in part to its original convex shape of FIG. 3, andresilient flexion members 14 and 20 have partially returned to theiroriginal unflexed position illustrated in FIG. 3. However, resilientflexion members 14 and 20 are normally still partially, downwardlycompressed and flexed in the manner illustrated in FIG. 6. At toestrike, prosthetic foot 10 is generally behind the individual's upperbody, as is normally the case when a person is walking. As theindividual continues his stride, lifts prosthetic foot 10 off ground 30,and puts his other foot on the ground, prosthetic foot 10 regains itsunflexed configuration illustrated in FIGS. 2 and 3.

As would be appreciated by those of skill in the art, it is possible tofabricate resilient flexion members 11, 14, 20 such that they areexceedingly stiff and will not resiliently flex at all when anindividual wearing a prosthetic device on his leg walks on prostheticfoot 10. This would, of course, defeat the purpose of the device. The“stiffness” or resistance to flexure of resilient flexion members 11,14, 20 can be adjusted as desired; however, the flexure of resilientflexion members 11, 14, 20 is adjusted such that prosthetic foot 10 willabsorb at least a portion of the impact encountered by an individualwhen prosthetic foot 10 strikes and rolls over the ground. In anexemplary embodiment, various materials may be used to constructprosthetic foot 10, and the different materials result in differentstiffness. Moreover, in an exemplary embodiment, resilient flexionmembers 11, 14, 20 are made of the same material or may be made ofdifferent materials. Some of the various materials include fiber glass,plastic, metal, carbon fiber, and the like.

In accordance with an exemplary embodiment, resilient flexion members11, 14, 20 are made of glass fiber composite. The glass fiber compositemay be a glass reinforced unidirectional fiber composite. In oneembodiment, the fiber composite material is made of a weave of fibersand resin to produce a strong and flexible material. The fibers may beglass fibers or carbon fibers. Specifically, layers of fiber areimpregnated with the resin, and a glass reinforcement layer ispositioned between at least two fiber weave layers. Typically, severallayers of the unidirectional fibers or tape are layered together toachieve the desired strength and flexibility. In one embodiment, thecomposite material is thermal formed and has a quick cure time, such asless than 60 minutes. In an exemplary embodiment, the composite materialis designed to provide a desired mix of strength and flexibility. Addingmore fiber to the material ratios increases the material strength butdecreases the flexibility, and vice versa. In one embodiment, thecomposite material is about 50% resin and about 50% fiber.

In one embodiment, fastener holes are planned into the prosthetic footpieces but not fully formed during the molding process. After removingthe prosthetic foot pieces from the mold, the fastener holes may beenlarged to a final size (for example, by drilling or machining). In anexemplary embodiment, the placement of the fastener and fastener holesare designed to offer greater product flexibility. Specifically, thefastener holes are placed away from the end of the toe. This placementcreates the option to machine the toe to create different prostheticfeet sizes based on a single mold design. In other words, the end of thetoe can be machined off to create a smaller foot.

In addition to the composite layers, other options may be included inthe prosthetic foot material. In an exemplary embodiment, a surfacingveil layer can be added to the top of toe member 14 (or any top surfaceof any component). The surfacing veil layer may also be described as ascrim layer. The surfacing veil layer chemically bonds to the exteriorlayer of the composite material. Moreover, the veil layer becomes anexposed, outer layer of the composite material. The veil layer may be anonwoven carbon or fiber glass scrim that has absorbed resin from thecomposite material. Furthermore, the surfacing veil layer providesmoisture protection. Another function of the surfacing veil layer may beto provide aesthetic options to the user. Specifically, the surfacingveil layer may include designs and patterns to enhance the aestheticappeal of the prosthetic foot.

FIG. 7 illustrates a bottom view of an exemplary prosthetic foot,specifically the instep of the layout. In an exemplary embodiment, themiddle section of bottom surface 24 is narrower than bottom ends 12, 13of bottom member 11. The narrow middle section of bottom member 11 isconfigured to provide enhanced ground compliance for prosthetic foot 10.Ground compliance is the ability to react to stepping on uneven footing,such as unlevel ground or an object. The narrow middle section allowsflexibility between first bottom end 12 and second bottom end 13 by wayof lateral twisting.

In accordance with another exemplary embodiment and with reference toFIGS. 8 and 9, a prosthetic foot 10A is similar to prosthetic foot 10and includes the same resilient bottom member 11. However, prostheticfoot 10A comprises a resilient heel member 20A that is shorter than heelmember 20. Furthermore, a resilient toe member 14A includes a first toeend 15A similar to first toe end 15 of resilient flexion toe member 14.Resilient toe member 14A also comprises a second toe end 16A, which issimilar to second toe end 16. However, second toe end 16A of resilienttoe member 14A is shaped differently from second toe end 16 and includesan approximately orthogonal tongue 44 having an aperture 45 formed therethrough. Aperture 45 may be configured to receive a bolt 41 that securesa connector 40 to tongue 44. In an exemplary embodiment, connector 40includes spaced apart legs 42, 43 that slide over the top of tongue 44.Each leg 42, 43 includes an aperture formed there through that is, ifconnector 40 is mounted on the top of tongue 44 in the mannerillustrated in FIG. 8, in registration with aperture 45 such that bolt41 can extend through all three apertures to secure connector 40 ontongue 44.

In one exemplary embodiment and with continued reference to FIGS. 8 and9, a resilient elastomeric polymer bridge 46 is fixedly secured to thebottom of resilient flexion toe member 14A (or, if desired, to the topof second heel end 22A) and includes a smooth arcuate outer surface 46Athat slides over the upper contact surface 34A of second heel end 22Awhen resilient flexion members 14A and 20A are compressed towardresilient flexion bottom member 11 by an individual's weight. Prostheticfoot 10A functions in substantially the same manner as prosthetic foot10.

In another embodiment, resilient flexion heel member 20, 20A is removedand is not utilized in a foot 10, 10A. In a further exemplaryembodiment, resilient flexion toe member 14, 14A is removed and is notutilized in a prosthetic foot 10, 10A, in which case second heel end 22Ais shaped and dimensioned like second toe end 16, 16A to be attached toa prosthetic leg worn by an individual.

Instead of resilient flexion toe member 14, 14A extending upwardly overresilient flexion heel member 20, 20A in the manner illustrated in FIGS.3-6 and 8, in still another exemplary embodiment, prosthetic foot 10,10A is shaped and dimensioned such that resilient flexion heel member20, 20A extends upwardly over resilient flexion toe member 14, 14A—inwhich case a portion of resilient flexion heel member 20, 20A is shapedto perform the function of second toe end 16 and to attach to aprosthetic leg worn by an individual.

Resilient flexion bottom member 11 and space 23 are important featuresof the prosthetic foot because they enable prosthetic foot 10 to rollover and traverse an upraised area 31 on the ground 30 without producinga “kick back” force that tends to force an amputee's leg rearwardly.Resilient flexion bottom member 11 deflects in the direction of arrow C(as shown in FIG. 3) to absorb forces produced by upraised area 31.

While it is presently preferred that resilient flexion bottom member 11have a convex shape and bottom surface 24 in the manner illustrated inFIGS. 1-5 and 7, resilient flexion bottom member 11 can still deflectand function to absorb some forces (particularly those forces producedby an upraised member 31) if resilient flexion bottom member 11 isrelatively flat in the manner indicated by dashed lines 11A in FIG. 8,or if resilient flexion bottom member 11 is concave in the mannerindicated by dashed lines 11 B in FIG. 8.

FIG. 10 illustrates a resistance-compression graph generallyrepresenting a typical prior art prosthetic foot. As is indicated byline 50 in FIG. 10, when a prior art prosthetic foot is compressed, theresistance response comprises a steadily increasing resistive force upuntil the prosthetic foot breaks 54. In contrast, the exemplaryprosthetic foot 10, 10A has a resistance-compression graph of thegeneral type illustrated in FIG. 11, in which the resistive forceincreases as indicated by line 51, levels off as indicated by line 52,and then increases as indicated by line 53 up until the prosthetic footbreaks 55. In FIGS. 10 and 11, “compression” on the vertical axis ofeach graph indicates the distance that the foot is compressed toward theground (or other surface) from its normal at rest configuration. Thegreater the compressive force that is applied to a prosthetic foot, themore the foot is flattened and pressed against the ground or anothersurface against which the foot is being pressed. In FIGS. 10 and 11,“resistance” in pounds on the horizontal axis of each graph indicatesthe compressive force required to compress the prosthetic foot throughthe distance indicated on the vertical axis.

In another exemplary embodiment, the prosthesis includes a resilientbladder 56 inserted intermediate resilient flexion members 20 and 11 (orresilient flexion members 14 and 11). The interior of bladder 56 ischarged with air, water, or another desired fluid. In the event a liquidis utilized, bladder 56 can, if desired, be partially or completelyfilled. When an individual walks on the prosthetic foot, the resilientbladder 56 is compressed and distends laterally to absorb compressivepressure that is applied to bladder 56 when resilient flexion heelmember 20 is displaced toward resilient flexion bottom member 11. Whenthe compressive pressure wanes, and resilient flexion heel member 20moves away from resilient flexion bottom member 11, bladder 56resiliently returns to its original shape and dimension. The bladder 56can, if desired, be inflated with a desired fluid to a selected pressuregreater than ambient pressure, in the same way that a tire on a vehicleis filled with air to a selected pressure greater than ambient pressure.

In accordance with an exemplary embodiment and with reference to FIG.12, a prosthetic foot 100 comprises a bottom member 110, a toe member120, and a heel member 130. The prosthetic foot 100 is configured topromote increased muscle activity and promote increased stability in theuser. The increased muscle activity is the result of prosthetic foot 100recruiting the use of secondary and tertiary muscle groups not typicallyemployed in a walking motion. The stance phase is approximately 60% ofthe walking cycle, and may be more difficult in terms of stability. Therecruitment of the secondary and tertiary muscle groups increases theirmuscle strength, which in turn increases the static and dynamicstability of the user. Furthermore, prosthetic foot 100 and strengthenedmuscle groups reduce the forward lean of the user.

As previously mentioned, the primary anterior muscle responsible fordorsiflexion (sagittal plane motion) is the anterior tibialis.Dorsiflexion is the voluntary ankle motion that elevates the footupwards, or towards the midline of the body. The primary posteriormuscle responsible for plantarflexion is the gastro-soleus complex. Itis a combination of two muscles working in conjunction: thegastrocnemius and the soleus. Plantarflexion is the voluntary anklemotion that depresses the foot downwards, or away from the midline ofthe body.

With respect to the walking motion, prosthetic foot 100 is configured toincrease the surface-to-foot contact through the gait cycle. Theincreased surface contact allows a smoother gait cycle, and increasesstability in comparison to the typical prior art. In exemplaryembodiments, the underside of bottom member 110 has different contoursthat provide increased surface contact for different types of uses. In afirst example and with reference to FIG. 13A, a general convex shape ofbottom member 110 facilitates a rocking motion from heel-to-toe duringthe gait cycle. The convex shape is designed to increase stability bysupplying surface contact of at least about 33% of the bottom surfaceduring the heel strike and toe off motions, and about 60% surfacecontact during the mid-stance phase. Furthermore, a load center 101 ofthe supported leg is at approximately ⅔ of the bottom surface from thetoe, ⅓ of the bottom surface from the heel. In other words, load center101 is not at a radial center of the walking path. This off-set loadcenter and surface area contact is designed to provide symmetry andbalance for the prosthetic foot user.

In a second example of different contours and with reference to FIG.13B, bottom member 110 may have a “wave” shape, or an undulatingcontour. The wave-contour of bottom member 110 is designed for activeusers, so that the elevated middle portion will absorb a strong impactlike running. The bottom member 110 has the toe and heel sections curvedslightly upwards, along with an elevated section 111 in the middle ofthe foot. In one embodiment, elevated section 111 is a gap of about ⅜inch from the surface. Moreover, in an exemplary embodiment, the “wave”shape of bottom member 110 may be mathematically described by a splineequation, specifically a non-uniform rational basis spline (NURBScurve).

Prosthetic foot 100, in one embodiment, further comprises a connectorspring clamp 125 that is coupled to toe member 120 and is configured toattach to a prosthetic leg. In one embodiment and with reference to FIG.14, connector spring clamp 125 is fastened to toe member 120 usingscrews 126. Furthermore, connector spring clamp 125 comprises a verticalspring, which may be a coil spring or other compression spring. The topof connector spring clamp may be a standard connecter confirming toindustry regulations for prosthetic leg attachment.

In addition, heel member 130 may comprise at least one bumper, such asprimary bumper 131 or secondary bumper 132. The primary bumper 131 isattached to heel member 130 and also in contact with the underside oftoe member 120. The primary bumper is designed to provide a dampingresistance while cushioning the deflection of toe member 120 during use.In an exemplary embodiment, the underside of toe member 120 includes agrooved area 122 that is in contact with primary bumper 131. The groovedarea provides additional surface area contact with primary bumper 131and therefore more stability. With respect to the other possible bumper,secondary bumper 132 is in coupled between heel member 130 and bottommember 110. The secondary bumper 132 is also configured to provide adamping resistance while cushioning the deflection of heel member 130during use.

In accordance with another exemplary embodiment, a prosthetic footdevice may comprise a toe member and a bottom member without a heelmember. Specifically, a bumper may be connected to either the bottommember or the toe member, and be configured to contact the oppositemember. The bumper connection between the toe member and the bottommember facilitates energy transfer during the gait cycle. In oneembodiment, the bumper is located towards the rear of the toe and bottommembers.

Additional prosthetic feet embodiments similar to prosthetic foot 100have also been contemplated. One such embodiment is a prosthetic footwith increased flexibility. One design capable of achieving additionalflexibility includes a lengthwise slot dividing a toe member. The slotincreases toe member flexibility in two ways. First, the slot reducesthe amount of material of the toe member, thereby reducing theresistance to plantarflexion and dorsiflexion movement. Second, locatingthe lengthwise slot at about the midline of the prosthetic foot enableslateral twisting, thereby mimicking a pronated position and a supinatedposition. In accordance with an exemplary embodiment, and with referenceto FIGS. 15A-15C, a prosthetic foot 500 comprises a bottom member 510, atoe member 520 with a toe slot 521, a heel member 530, and a connector525. Prosthetic foot 500 may further comprise a primary bumper 531and/or a secondary bumper 532. Also, as shown in FIG. 15C, toe member520 may include a grooved area 522 on the backside that is configured tobe in contact with primary bumper 531. The grooved area 522 providesadditional surface area contact with primary bumper 531 and thereforemore stability.

In the following description and/or claims, the terms coupled and/orconnected, along with their derivatives, may be used. In particularembodiments, connected may be used to indicate that two or more elementsare in direct physical and/or electrical contact with each other.Coupled may mean that two or more elements are in direct physical and/orelectrical contact. However, coupled may also mean that two or moreelements may not be in direct contact with each other, but yet may stillcooperate and/or interact with each other. Furthermore, couple may meanthat two objects are in communication with each other, and/orcommunicate with each other, such as two pieces of hardware.Furthermore, the term “and/or” may mean “and”, it may mean “or”, it maymean “exclusive-or”, it may mean “one”, it may mean “some, but not all”,it may mean “neither”, and/or it may mean “both”, although the scope ofclaimed subject matter is not limited in this respect.

It should be appreciated that the particular implementations shown anddescribed herein are illustrative of various embodiments including itsbest mode, and are not intended to limit the scope of the presentdisclosure in any way. For the sake of brevity, conventional techniquesfor signal processing, data transmission, signaling, and networkcontrol, and other functional aspects of the systems (and components ofthe individual operating components of the systems) may not be describedin detail herein. Furthermore, the connecting lines shown in the variousfigures contained herein are intended to represent exemplary functionalrelationships and/or physical couplings between the various elements. Itshould be noted that many alternative or additional functionalrelationships or physical connections may be present in a practicalcommunication system.

While the principles of the disclosure have been shown in embodiments,many modifications of structure, arrangements, proportions, theelements, materials and components, used in practice, which areparticularly adapted for a specific environment and operatingrequirements without departing from the principles and scope of thisdisclosure. These and other changes or modifications are intended to beincluded within the scope of the present disclosure and may be expressedin the following claims.

What is claimed is:
 1. A prosthetic foot comprising: a bottom membercomprising a first bottom end and a second bottom, wherein a radius ofcurvature of the bottom member from the first bottom end to the secondbottom end is above the bottom member; a top member comprising a firsttop end and a second top end, wherein the first top end is connected tothe first bottom end of the bottom member, and wherein the top member ispositioned over the bottom member; and a bumper coupled to an uppersurface of the second bottom end of the bottom member and in contactwith an underside of the top member; wherein the prosthetic foot isconfigured to store energy during a heel strike phase of a gait cycle,and release energy during a toe-off phase of the gait cycle in order toassist forward movement.
 2. The prosthetic foot of claim 1, wherein thebottom member is convex from the first bottom end to the second bottomend with respect to the ground.
 3. The prosthetic foot of claim 1,wherein the bottom member has no inflection point.
 4. The prostheticfoot of claim 1, wherein the bumper is not coupled to the underside ofthe top member.
 5. The prosthetic foot of claim 1, wherein the bumpermay disengage from contact with the underside of the top member duringthe toe-off phase.
 6. The prosthetic foot of claim 1, wherein the radiusof curvature of the bottom member from the first bottom end to thesecond bottom end is above the bottom member in an unloaded state. 7.The prosthetic foot of claim 1, wherein the bumper comprises anelastomeric material.
 8. The prosthetic foot of claim 7, wherein thebumper is configured to provide a damping resistance.
 9. The prostheticfoot of claim 7, wherein the bumper is configured to cushion thedeflection of the top member during use.
 10. The prosthetic foot deviceof claim 1, further comprising a heel member connected to the secondbottom end of the bottom member, wherein the heel member extendsupwardly from the second bottom end.
 11. The prosthetic foot of claim 1,wherein 90% or more of the energy stored during a heel strike phase istransferred to the top member for assisting the toe-off phase.
 12. Theprosthetic foot of claim 1, wherein at least one of the bottom memberand the top member is made of a glass fiber composite, wherein saidglass fiber composite comprises a fiber weave layer of about 50% fiberand about 50% resin, and a glass reinforcement layer positioned betweenat least two fiber weave layers.
 13. The prosthetic foot device of claim1, wherein at least 33% of the bottom member is in contact with asurface during heel strike and toe-off motions of a gait cycle.
 14. Theprosthetic foot device of claim 1, wherein at least 60% of the bottommember is in contact with a surface during a mid-stance phase of a gaitcycle.
 15. The prosthetic foot device of claim 10, wherein the heelcomprises a secondary bumper configured to provide a damping resistancewhile cushioning the deflection of the heel member during use.
 16. Theprosthetic foot of claim 1, wherein a loading response during the heelstrike phase compresses the top member and causes a deflection of thesecond bottom end of the bottom member.
 17. The prosthetic foot of claim16, wherein an upward deflection of the bottom member and said topmember stores energy during a transition from the heel strike phase to atoe-off phase of the gait cycle, and wherein 90% or more of the energystored during the heel strike phase is transferred to the top member forassisting the toe-off phase.
 18. A prosthetic foot comprising: a curvedbottom member comprising a first bottom end and a second bottom end, andhaving no inflection point, wherein a radius of curvature of the curvedbottom member from the first bottom end to the second bottom end isabove the curved bottom member; a top member comprising a first top endand a second top end, wherein the first top end is connected to thefirst bottom end of the curved bottom member, and wherein the top memberis positioned over the curved bottom member; and a bumper coupled to anupper surface of the back end of the curved bottom member and in contactbut not coupled with an underside of the second top end of top member.19. The prosthetic foot of claim 18, wherein the curved bottom member isconvex from the first bottom end to the second bottom end with respectto the ground.